Method for determining the respective temperature of several battery cells of a vehicle battery via extrapolation of a measured temperature; control device and vehicle battery

Abstract

A method for determining respective temperatures of a plurality of battery cells includes determination of measured values including a first voltage of a first battery cell, a second voltage of a second battery cell, and a respective current that flows through the first and second battery cells. A first measured resistance of the first battery cell and a second measured resistance of the second battery cell is determined from the measured values. A reference resistance is determined. A first resistance relationship from the first measured resistance and the reference resistance and a second resistance relationship from the second measured resistance and the reference resistance are determined. A measured temperature of the first battery cell is determined. A computed temperature of the second battery cell is determined based on the measured temperature of the first battery cell, the first resistance relationship, and the second resistance relationship according to a predetermined requirement.

The invention claimed is: 
     
         1 . A method for operating a temperature monitoring system to determine respective temperatures of battery cells of a vehicle battery, wherein the vehicle battery includes a set of first battery cells and a set of second battery cells, wherein the temperature monitoring system comprises: a control unit, a measuring device, and one or more temperature monitoring units, wherein each first battery cell is and each second battery cell is not associated with a respective temperature monitoring unit, the method comprising the steps of:
 measuring, via the measuring device, a first voltage of each first battery cell, a second voltage of each second battery cell, and at least one respective current through the first battery cells and the second battery cells;   determining, via the control unit, a first resistance of the first battery cells and a second resistance of the second battery cells from the first voltages and the second voltages;   determining, via the control unit, a first resistance relationship from the first resistance and a reference resistance, and a second resistance relationship from the second resistance and the reference resistance;   measuring, via the temperature monitoring unit, a temperature of each first battery cell; and   determining, via the control unit, a computed temperature of each second battery cell from the temperatures of the first battery cells, the first resistance relationship and the second resistance relationship, according to a predetermined requirement.   
     
     
         2 . The method of  claim 1 , wherein the reference resistance is an average value of the first resistance and the second resistance. 
     
     
         3 . The method of  claim 1 , wherein the predetermined requirement contains a distribution function and/or a value table that assigns exactly one respective value for the computed temperatures to a plurality of values for the second resistance relationship depending on the temperatures of the first battery cells and the first resistance relationship. 
     
     
         4 . The method of  claim 3 , wherein the distribution function and/or the value table is first normalized depending on the first resistance relationship and the temperatures of the first battery cells and the computed temperatures are then derived from the normalized distribution function and/or the value table depending on the second resistance relationship. 
     
     
         5 . The method of  claim 1 , wherein the set of second battery cells comprises a plurality of second battery cells. 
     
     
         6 . The method of  claim 1 , wherein the set of first battery cells comprises a plurality of first battery cells. 
     
     
         7 . The method of  claim 6 , wherein at least one measured temperature of first battery cells disposed on an edge of the vehicle battery and at least one measured temperature of first battery cells disposed in a center of the vehicle battery is determined. 
     
     
         8 . The method of  claim 1 , further comprising:
 checking whether a reference state is present, wherein a correlation coefficient is greater than a determined value and/or respective measured temperatures of the first battery cells do not exceed a determined measure in the reference state.   
     
     
         9 . An apparatus for determining respective temperatures of battery cells of a vehicle battery that includes a set of first battery cells and a set of second battery cells, the apparatus comprising:
 a measuring device configured to measure a first voltage of each first battery cell, a second voltage of each second battery cell, and at least one respective current through the first battery cells and the second battery cells;   one or more temperature monitoring units configured to measure respective temperatures of each first battery cell, wherein each first battery cell is and each second battery cell is not associated with a respective temperature monitoring unit; and   a control device, wherein the control device is configured to:
 determine a first resistance of the first battery cells and a second resistance of the second battery cells from the first voltages and the second voltages; 
 determine a first resistance relationship from the first resistance and a reference resistance, and a second resistance relationship from the second resistance and the reference resistance; and 
 determine a computed temperature of each second battery cell from the temperatures of the first battery cells, the first resistance relationship, and the second resistance relationship, according to a predetermined requirement. 
   
     
     
         10 . A vehicle battery, comprising:
 a set of first battery cells and a set of second battery cells; and   the apparatus of  claim 9 .